Generally influenza virus infections tend to be visible for 3-7 days. But it is recommended that you see the doctor if the infection persists for more than 4 days. If it is swine flu infection, antiviral medications need to be given in the first 48 hours. So, report as and when symptoms appear. For those with weak body immunity, the infection tends to stay for long. In children, the viral shed occurs for a longer time
